ATHENS,Robovis Greece (AP) — Two leading international human rights groups on Thursday accused Greek authorities of failing to properly investigate the circumstances around a migrant boat sinking six months ago that killed hundreds.

In a joint report, Amnesty International and Human Rights Watch said “little meaningful progress” has been made in examining allegations by some survivors that the rescue mission was delayed and mishandled.

Up to 750 people were believed to have been crammed into the “Adriana,” a rusty fishing trawler that sank on June 14 southwest of the Greek mainland while traveling from Libya to Italy.

Following the sinking, 104 people were rescued — migrants mostly from Syria, Pakistan, and Egypt — and 82 bodies were recovered.

The two rights groups said they interviewed 21 survivors and five relatives of people still missing as well as representatives of the Greek coast guard and the Greek police.

“The survivors and the families of the missing and dead deserve a full accounting of what happened,” Judith Sunderland, an associate director at Human Rights Watch for Europe and central Asia, told the Associated Press.

“Our research confirms that a catalog of failures led to the fatal shipwreck,” Sunderland said, adding that the vessel was clearly “overcrowded, unseaworthy, and in danger” hours before it capsized.

Some of the survivors have disputed the official Greek account that people on the trawler refused offers of assistance.

The allegations triggered the launch of an independent investigation last month by Greece’s state ombudsman. It said the coast guard failed to conduct its own disciplinary investigation into the agency’s response June 14. In September, 40 survivors initiated legal action against Greek authorities.

There was no immediate reaction from Greek authorities to Thursday’s report. But government officials have described criticism of the coast guard as unfair and maintain that blame should squarely fall on smugglers who cram migrants onto unseaworthy boats. The coast guard has denied claims made by some survivors that it made a failed attempt to tow the vessel before it sank. ___

Follow AP’s global migration coverage at https://apnews.com/hub/migration